In order to pattern a workpiece in, for example, a lithographic process, using either lasers, electron beams, ions or other methods, the workpiece may be aligned with a writing tool in, for example, six different ways. The workpiece may be horizontally aligned with the writing tool in an x-direction and in a y-direction. The workpiece may also be aligned, for example, rotationally aligned. The workpiece may be placed in focus of the writing tool, that is, be aligned in a z-direction. The workpiece and writing tool may be tilt aligned in, for example, two perpendicular directions. The workpiece and the writing tool may not be tilt aligned, and the pattern created by the writing tool may be out of focus for different parts of the workpiece and in focus for other parts.
The alignment of the workpiece in the x-direction, y-direction and the rotational alignment may be performed by placing the workpiece in a pre-aligner, which may include a number of alignment pegs extending from a surface on top of which said workpiece may be replaced. The alignment pegs may be attached to the surface of the pre-aligner for aligning the workpiece in a position. The pre-aligner may blow air through a number of orifices beneath the workpiece, and a cushion may be formed between the surface of the pre aligner and the workpiece. The cushion may transport the workpiece in a direction with a reduced amount of friction and/or force applied. If the pre-aligner is tilted in a direction so that the alignment pegs may be lowered, the workpiece may move towards the alignment pegs. If the alignment pegs are attached to the surface correctly, the workpiece may be placed in the position when contacting the alignment pegs. A gripper may grip the workpiece in a position and may transport the workpiece to a stage for further alignment.
Another conventional method for aligning the workpiece may use a stage, which may be movable in both the x- and y-direction and rotatable along a central axis. The workpiece may be placed, within tolerances, at the stage. A detector may detect the position of the edges of the workpiece while moving the stage. The stage may be in an aligned position, for example, when the actual position of the edges of the workpiece may be in a position.